Nutritional and smoking advice to patients with or at risk of age-related macular degeneration by optometrists in Singapore

Abstract

Age-related macular degeneration (AMD) is the leading cause for visual impairment and blindness registration in the developed world. Globally, 8.7% of the population has AMD and it has been projected that the number of people afflicted with AMD by 2020 will be 196 million, increasing to 288 million by 2040. AMD is multi-factorial and the key pathogenesis of AMD is not known, but it has been postulated to be related to oxidative stress. As there is no known treatment for atrophic AMD, many researchers have investigated the modifiable risk factors such as smoking and diet to prevent progression to neovascular AMD. Following large clinical trials such as AREDS and AREDS 2, many supplements to support eye health emerged in the market. With such a large selection of products and various information, this could be confusing for the patients and even eye care practitioners. This doctorate programme consists of three distinct studies (chapters three to five) and the first objective of this research was to evaluate the nutritional and smoking advice for patients with or at risk of AMD by optometrists in Singapore. This objective was achieved via a questionnaire (online and hardcopy) (chapter three) as well as face-to-face in-depth interviews (chapter four). The questionnaire consisted of 41 questions and participants received the hardcopies through mail or an online link through social media or email to complete the questionnaire electronically. The questionnaire elicited demographic information, frequency of dietary advice to patients with early, advanced or at risk of AMD, as well as smoking advice to AMD patients. The response rate of the questionnaire was 18.2%. 52.9% of the respondents provide dietary advice to patients with advanced AMD most of the time, and 31.7% of the respondents provide dietary advice to patients at risk of AMD most of the time. Optometrists in Singapore advise AMD patients to consume green leafy vegetables and oily fish but seldom advise on the amount to consume. Slightly more than one-third of the optometrists in Singapore will inform smokers of the link between smoking and AMD and slightly more than half will advise AMD patients to stop smoking. From the face-to-face in-depth interviews, Singapore optometrists do believe that nutrition are beneficial for the eye but they need more knowledge and a guideline in this area to be more confident when providing nutritional advice for AMD patients. The second objective of this research was to evaluate a Clinical Decision-Making Aid (CDMA) in the form of a flowchart to determine its impact on the self-efficacy of qualified and student optometrists in providing dietary advice regarding risk or progression of AMD (chapter five). The results show that the self-efficacy scores increased after using the CDMA for both qualified and student optometrists and the number of correct answers for five simulated clinical scenarios also increased after using the CDMA. Despite some conflict regarding nutritional research for AMD, provision of appropriate nutritional and smoking advice is important with regard to reducing risk of progression to sight loss related to AMD. Moreover, optimising nutritional intake and avoiding smoking are beneficial for general well-being. This thesis shows that, with the CDMA, eye care practitioners are able to provide more accurate and research-based nutritional information to their AMD patients with more confidence.